With increasing demands for cost reductions, the US healthcare system has moved many complicated medical technologies from the hospital to the home. However, to successfully use these technologies, patients and their caregivers must perform complicated medical tasks that typically would be the role of skilled inpatient nurses. One medical technology, outpatient parenteral antimicrobial therapy (OPAT), allows patients needing long-term parenteral antimicrobials to complete these regimens after discharge via venous catheters. These patients and their caregivers perform infusions and catheter care at least daily for several weeks. They are at risk of significant complications such as catheter complications, adverse drug events, and relapse of the infection. It is unclear which patient-level risk factors may affect outcomes, how patients and caregivers actually perform OPAT-related tasks, or how to improve patient/caregiver performance of OPAT-related tasks. This proposal will identify risk factors for OPAT complications and determine which processes of OPAT administration are more likely to fail. The project will engage patients, caregivers, and home health providers as key stakeholders in understanding the risk factors for poorer outcomes and how to modify these risks to successfully complete OPAT tasks, and in developing and piloting an OPAT intervention. Specific Aim 1: To create a risk score to predict the development of OPAT complications through a prospective cohort of OPAT patients discharged from two academic medical centers. A prospective cohort of OPAT patients will be used to create a risk derivation and validation cohort to develop a risk score for OPAT complications that can be used at hospital discharge to identify patients who may need additional assistance with OPAT. Specific Aim 2: To complete a proactive risk assessment that (1) identifies ways in which OPAT patients might be harmed, and (2) informs an intervention which improves safety among patients receiving OPAT. Semi-structured interviews of patients and home observations of patients and caregivers performing OPAT tasks will be used to identify hazards in OPAT performance. This information, and the risk score from Aim 1, will be presented to groups of patients and caregivers, home health nurses, and home infusion pharmacists to develop and prioritize interventions to improve the quality of OPAT care. This intervention will be piloted among a small group of home health nurses and patients to assess its feasibility and acceptability. The overall goal of this proposal is to prepare Dr. Keller for a career as an independent investigator in patient safety by using human factors engineering and stakeholder engagement to improve the quality and safety of OPAT.